Search PubMed⌕ Search

Biomedical subjects

N Girard

Publications and source records attributed to N Girard.

142 records · Page 8Linked to original sources
PubMed1982

Inhibition of active E rosette forming T lymphocytes by hyaluronic acid. Evidence of a receptor for hyaluronic acid on a lymphocyte subpopulation.

Previous studies have shown the inhibition of active E rosette forming T lymphocytes by a mesenchyme associated antigen. Recent results clearly indicated that this antigen consisted in the association of a glycoprotein named hyaluronectin with hyaluronic acid. Using the active E rosette technique of Wybran and Fudenberg, we have studied the action of hyaluronic acid on T lymphocytes. We obtained evidence of the partial inhibition of active E rosette formation by hyaluronic acid in 19 of 25 healthy subjects. Among them, inhibition percentage was 45 +/- 4. This inhibition remained significant at a concentration of 22.5 micrograms/ml hyaluronic acid. Hyaluronic acid was labelled with peroxidase by the glutaraldehyde technique: 17 +/- 7% lymphocytes were stained by this preparation. The preincubation of peroxydase labelled hyaluronic acid by brain hyaluronectin lowered this staining. This is in agreement with the presence of hyaluronectin on a subpopulation of lymphocytes as it was shown by immunofluorescence techniques. In conclusion, a receptor for hyaluronic acid (hyaluronectin) was detected on a proportion of lymphocytes. These results suggest that hyaluronic acid could have an immunosuppressive activity.

Humans↗
PubMed1981

[Nervous system tumour proteins. G.F.A. and hyaluronectin (author's transl)].

G.F.A. (gliofibrillary acid protein) and hyaluronectin studied here are two antigens defined by the heteroantibodies which appear in the serum of the immunised animal. G.F.A. is associated with gliofilaments and is considered as an astrocyte marker, either normal or tumoral. Hyaluronectin, is found in the Ranvier nodes and at the periphery of neurones. It is not specific to the nervous system. It is found in all tissues and tumors, and in particular marks the intercellular spaces of gliomas, where it is associated with hyaluronic acid for which it has a great affinity. Serum estimation of these Proteins is being undertaken with the view to a clinical application.

Animals↗
PubMed1980

Brain glycoprotein in tumours of the nervous system.

We studied various tumours of the nervous system by the immunofluorescence technique using an anti-brain specific alpha 2 glycoprotein antiserum (anti-NSA3 antiserum). We found the antigen in 24/27 astrocytomas and 4/4 oligodendrogliomas but in none of the 8 meningiomas tested. There was an identity between the astrocytoma/oligodendroglioma antigen and that of normal brain as shown by the immunoprecipitation technique. By the immunofluorescence technique using inhibition of the antiserum we demonstrated that the tumour antigen is devoid of some specific nervous system determinants present in normal brain.

Antigens, Neoplasm↗
PubMed1979

[Association of brain glycoprotein (NSA 3) with neuronal membranes and with the nodes of Ranvier].

The localisation of brain glycoprotein NSA 3 was studied by means of indirect immunofluorescence on alcohol fixed, paraffin embedded sections of Rat brain. These techniques allowed the localisation of NSA 3 to the membrane of some (about 10%) of the neurons. In the white matter, the patterns were in agreement with the localisation of the Ranvier nodes. The nodes of Ranvier were also stained in peripheral nerves.

Brain Chemistry↗
PubMed1979

An antigen associated with mesenchyme in human tumours that cross-reacts with brain glycoprotein.

Anti-NSA3 antiserum was found to react with many kinds of benign and malignant tumours, as well as foetal skin and intestinal extracts. The corresponding antigens isolated from nervous tissue, benign breast adenoma, and a fibrosarcoma were compared. Immunoprecipitation cannot distinguish between these antigens, and their amino-acid contents were comparable. However, immuno-absorption identified an antigenic determinant that was confined to nervous tissue. Indirect immunofluorescence further confirmed the validity of the concept of a nervous form vs a mesenchymal form of the antigen. Furthermore, immunofluorescence enabled the localization of the antigen found in non-nervous tissue to mesenchyme (mesenchyme-associated antigen: MAA), whether the mesenchymal tissue be normal (foetal organs), tumoral (fibrosarcoma) or reactional (connective-tissue stroma of epithelial tumours).

Amino Acids↗
PubMed1979

Isolation and characterization of a mesenchyme associated antigen from dimethylbenzanthracene induced rat fibrosarcoma.

Using an antiserum directed against human neurospecific antigen and the indirect immunofluorescence technique, we have obtained evidence for the presence of a mesenchyme associated cross-reacting antigen (MAA) in the dimethylbenzanthracene induced fibrosarcoma of the rat. This antigen has been purified from this tumor and compared with the antigen associated with the human nervous system and that associated with the nervous system of the rat. An anti-rat MAA antiserum has been obtained. It has cytotoxic activity against cultured fibrosarcoma cells as measured by release of radioactivity. This antigen can be considered as a marker of fibrosarcomas.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

[Mesenchyme-associated antigen: a new immunochemical marker of human tumors].

An antiserum raised in Rabbits against brain glycoprotein precipitated an identical antigen in faetal dermis and intestine extracts, and also in non nervous tumors (breast adenocarcinomas and adenofibromas, ovarian cystadenoma, gastric and colonic adenocarcinomas, hepatomas, malignant melanomas, rhabdomvosarcoma, fibrosarcomas). By the indirect immunofluorescence technique, this antigen was always found associated with the mesenchymal proliferation, either malignant (fibrosarcoma) or reactive (fibrous stroma reaction of carcinomas).

Animals↗
PubMed1978

[Disappearance of the gliofibrillar protein (GFA) during the cultivation of glioblastoma cells].

Absence of GFA in established cell lines from glioblastomas promped us to look for this protein from the first replication of malignant cells in vitro and in following subcultrues. Our results show that GFA disappeared during the first twelve replications, often before the fifth replication. No correlation was observed with a morphological transformation of the cells.

Antigens, Neoplasm↗
PubMed1978

Glial fibrillary acidic protein in tumours of the nervous system.

Glial fibrillary acidic protein (GFA) was assayed in nerve-tumour extracts and located in these tumours by indirect immunofluorescence study. We conclude that GFA is a specific marker of both malignant and normal astrocytes. Non-astrocytic tumours (oligodendroglioma, meningioma) do not contain GFA. Tumours with astrocytic differentiation potential (medulloblastoma) may contain GFA. Comparison of microscopic and GFA assays leads us to conclude that GFA concentration is proportional to the amount of malignant astrocytes in the tumour and inversely proportional to the necrotic area of a tumour. Normal tissue GFA and glioblastoma GFA were found to be immunologically identical.

Antigens↗
PubMedDate not supplied

[Efficacy of early cerebral MR in the detection of brain lesions in high risk preterm infants compared with conventional US].

To identify the efficacy of early cerebral MR, performed in the first month of birth, in the detection of brain lesions in high risk preterm infants, compared with conventional US, we recruited into the study a group of 30 preterm infants born at or below a gestational age of 30 weeks, who had a pathologic scan. The findings on US were compared with those of the early MR scan, performed in the same days, the results of which were considered as the final diagnosis. The value of cranial US as a predictor of MR signal intensity was assessed by calculating sensitivity, specificity, positive and negative predictive values. Agreement between two investigations was evaluated by calculating the K coefficient. US showed 33 haemorrhagic lesions in 25 preterms; MR showed 27 haemorrhagic lesions in 22 infants: in 16 cases MR gave the same results of US. Cranial US was reliable in detecting lesions such as GLH and IVH, but less sensitive in the definition of their size and distribution. Sensitivity of US for haemorrhagic lesions was 96.3%, PPV 78.8%, K coefficient 0.55 (p < 0.001). About the White Matter, cranial US demonstrated 20 lesions in 20 preterms; MR showed 16 lesions in 16 infants: in 3 cases MR was agree to US. US showed high reliability in the detection of cystic lesions, but significant limitations in the demonstration of non-cystic injury. We founded that normal WM echogenicity on US is not a good predictor of normal WM signal intensity on MR (30%). Sensitivity of US for WM lesions was 81.3%, PPV 65%, K coefficient 0.23 (p = 0.04). Finally US showed 4 lesions in other brain locations, MR confirmed 3 of them and discovered other 10. Sensitivity of US for these lesions was 23.1%, PPV 75%, K coefficient 0.21 (p = 0.11). We founded that cranial US is a good method for detecting GLH, IVH, HPI and severe WM lesions (cystic PVL), but it can miss non-cystic PVL, punctate haemorrhages, WMD and lesions in other brain locations, that, on the other hand, MR detects clearly.

Brain Diseases↗
PubMedDate not supplied

[X-ray computed tomography of fractures of the calcaneum. Apropos of 30 cases].

Computed tomography and lateral plain films have been studied in 30 fractures of calcaneus. C.T. allows us to study in the same time the two feet, with low mobilisation. Two planes are mandatory: --one, along the long axis of the calcaneus, allows a good evaluation of calcaneo-cuboïd joint, of the quality of the bone structure and of the large fragments or comminution; --the other one (coronal in 18 cases of along the tuberosity in 16 cases) shows directly the subtalar joint lesions (impaction, joint incongruence) and plantar fracture line. This study conclude that CT is useful for the evaluation of the severity calcaneus fractures and for treatment selection because of a better evaluation of lesions.

Adult↗